There are the usual suspects – oil spills, toxic sludge lakes, deforestation, mountaintop removal etc – but for me the most poignant and depressing is a picture by Karl Ammann of a family of dead gorillas huddled together after being slaughtered for bushmeat in southeast Cameroon.

It is sad on two levels: there's the plight of the gorillas, of course, but there's also the fact that some people live such desperate lives that they have to resort to such barbarity. I challenge anyone not to be moved by this photograph.

If I had to nominate my own contenders for the honour of "saddest environmental photo ever" they would probably include something like the photograph of a dying horse amid the burning Kuwaiti oil fields following the Gulf War in 1991.

It was shot by Steve McCurry (best known for his famous 'Afghan girl' shot that first appeared on the cover of National Geographic in June 1985) and it shows humanity at one its lowest ebbs.